Method for treating joint pain and associated instruments

ABSTRACT

The embodiments provide provides devices, instruments, and associated methods for treating joint pain. A joint is evaluated using magnetic resonance imaging to detect any defects in the subchondral bone. For example, using T2-weighted MRI images, bone marrow lesions or edemas can be identified, and using T1-weighted MRI images, associated regions of sclerotic bone adjacent to the bone marrow lesion can be identified. The treatment method may involve introducing a bone void filler material at the site to address the bone marrow lesion or edema, and/or drilling and inserting an implant to address the sclerotic bone, bone marrow lesion or edema, and insufficiency or stress fractures. An access path is mapped to a location in the subchondral region where the insufficiency fracture resides. The access path attempts to preserve an articular surface of the joint. A reinforcing member that stabilizes the insufficiency fracture is then implanted via the access path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional No. 61/263,170filed Nov. 20, 2009, and entitled “METHOD FOR TREATING JOINT PAIN ANDASSOCIATED INSTRUMENTS,” which is herein incorporated by reference inits entirety.

This application also relates to co-pending and co-owned U.S. patentapplication Ser. No. ______, filed Nov. 19, 2010 and entitled“SUBCHONDRAL TREATMENT OF JOINT PAIN,” the content of which is hereinincorporated in its entirety by reference.

FIELD

Embodiments of the present invention relate to devices, instruments, andassociated methods for treating joint pain, and more particularly, kneepain.

BACKGROUND

Knee arthritis affects millions of people and the pain associated withthis disease can be disabling. Patients who initially present withpainful knee arthritis are usually treated non-surgically. Non-surgicaltreatments are modestly effective at temporarily relieving pain, but arenot risk free. Pharmacologic intervention (i.e., non-steroidalanti-inflammatory drugs) has been reported to be associated withsignificant complications, such as gastric ulcers, strokes and heartattacks. A steroid or viscosupplement injection may lead to infection.Steroid injections may also have systemic effects, such as increasedblood sugar and hypertension. Generally speaking, non-surgicalinterventions are most efficacious for early arthritic disease and donot prevent disease progression.

When non-surgical treatment proves ineffective, surgical intervention isoften recommended. Arthroscopic surgery has been shown to have limitedeffectiveness and has a small role in the management of knee arthritis.More invasive surgical approaches such as high tibial osteotomy andpartial or complete knee replacement predictably relieve pain. Thesemajor operations, however, are also potentially associated withsignificant morbidity and occasional mortality. These risks, along withthe limited durability of implantable devices, cause patients andphysicians to defer surgery until the symptoms become unbearable.

Some research has determined that glutamate transporters and receptorsare highly expressed in subchondral proximal tibial bone in patientswith osteoarthritis. The degree of expression of these transporters andreceptors is directly proportional to the severity of the disease.Further, the increased expression occurs in the subchondral boneadjacent to the arthritic lesion. Thus, subchondral bone is likely animportant source of pain management of osteoarthritis. See, “Expressionof Glutamate Receptors and Transporters in Human Subchondral Bone inOsteoarthritis” by Christopher Wilson (Oct. 13, 2009).

Accordingly, it is desired to provide an effective, surgical treatmentof osteoarthritis, and particularly knee arthritis pain. It is furtherdesired that such surgical treatment be less invasive than high tibialosteotomy and partial or complete knee replacement.

SUMMARY

The present disclosure provides devices, instruments, and associatedmethods for treating joint pain. In particular, the joint is evaluatedusing magnetic resonance imaging to detect any anomalies in thesubchondral bone. For example, using T2-weighted MRI images, bone marrowlesions or edemas can be identified, and using T1-weighted MRI images,associated regions of sclerotic bone adjacent to the bone marrow lesioncan be identified. This condition may be the result of several factors,such as early arthritis, that results in an uneven concentration ofloads in a joint. The uneven loads may cause a region of the bone toharden and become sclerotic, which can further aggravate the uneven loaddistribution. As a result, the sclerotic bone and uneven load may causeinsufficiency fractures or fissures that appear as a bone marrow lesionor edema.

In one embodiment, the subchondral region of the bone is evaluated forthe presence of one or more bone marrow lesions and a region ofsclerotic bone. If these indications are found, then a SUBCHONDROPLASTY™treatment may be employed to treat the joint pain. The method mayinvolve introducing a bone void filler material at the site to addressthe bone marrow lesion or edema, and/or drilling and inserting animplant to address the sclerotic bone. This treatment may thus serve toreintegrate the bone and equalize load distribution to thereby relievepain.

In one embodiment, a method for treating joint pain comprises:identifying a source of the pain of the joint based on an image of thejoint, the image indicating the presence of a defect in the subchondralregion of a bone of the joint; locating an insufficiency fracture in thesubchondral region of the joint; mapping an access path to a location inthe subchondral region where the insufficiency fracture resides, whereinthe access path preserves an articular surface of the joint; andimplanting in the bone, via the access path, a reinforcing member thatstabilizes the insufficiency fracture.

In another embodiment, an instrument for guiding a tool to a targetlocation in a bone adjacent to a joint comprises: a first portion havinga first guide section configured to guide the tool to the targetlocation; a reference probe extending from the first portion having atip that indicates a selected landmark on the bone; and a handle portioncoupled to the first portion and having a second guide sectionconfigured to guide a tool to the target location. The first guidesection is configured to guide the tool at an angle substantiallyparallel to the reference probe, and the second guide section isconfigured to guide the tool at an angle acute to the reference probe.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure. Additional features of thedisclosure will be set forth in part in the description which follows ormay be learned by practice of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a magnetic resonance image (MRI) of an arthritic knee on whichis overlaid a side view of an embodiment of the reinforcing member ofthe invention;

FIGS. 2A and 2B show exemplary SUBCHONDROPLASTY™ kits;

FIG. 3A shows a SUBCHONDROPLASTY™ template of the kit from FIG. 2A inuse;

FIG. 3B shows a SUBCHONDROPLASTY™ template of the kit from FIG. 2B inuse;

FIG. 4A shows an exemplary embodiment of the SUBCHONDROPLASTY™guide/insertion tool or instrument;

FIG. 4B shows another exemplary embodiment of the SUBCHONDROPLASTY™guide/insertion tool or instrument;

FIG. 5 illustrates a side view of a SUBCHONDROPLASTY™ guide/insertioninstrument and various options of the guide/insertion instrument in usewith other instruments of the kit;

FIG. 6 illustrates a perspective view of the various options of theSUBCHONDROPLASTY™ guide/insertion instrument in use with otherinstruments of the kit;

FIG. 7A shows one embodiment of a SUBCHONDROPLASTY™ guide/insertioninstrument and a side view of how the guide/insertion instrument may beplaced relative to a knee;

FIG. 7B shows another embodiment of a SUBCHONDROPLASTY™ guide/insertioninstrument and a perspective view of how it may be placed relative to aknee;

FIGS. 8, 9A-9J, 10A-10B, and 11A-11C illustrate a method of treating aknee based on embodiments of the present invention; and

FIGS. 12-16 illustrate a method of treating a subchondral region of abone based on another embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

In general, the embodiments relate to devices, instruments andassociated methods for treating joint pain in the subchondral region ofthe bone. One embodiment involves identifying defects in the subchondralregion of a bone, such as a bone marrow lesion or edema adjacent to thejoint, where sclerotic bone is also present, and then treating thedefects such as by implanting an implant, such as a reinforcing member,in or adjacent to the abnormality or bone marrow lesion. Anothertreatment may involve the introduction of bone void material. In someembodiments, bone marrow lesions are considered an indicator ofoverstressed bone. In general, a bone marrow lesion may be any abnormalarea or fracture in the bone. That is, any fracture non-union having apathology indicating an amorphous structure with osseous and fibrouselements may be treatable by embodiments of the present invention.

Overstressed bone sustains more damage than repair and this oftenresults in pain to a patient. Bone is continuously fatigued and damagedby everyday activity. However, bone is a living tissue that is capableof repairing itself. Certain pathological processes, such as loss ofjoint cartilage or joint deformation, can disturb the natural repairprocesses of healthy bone.

Embodiments of the invention may enhance the strength of bone andprovide shielding to the subchondral region of the bone to prevent orminimize excessive stress using a subchondral surgical treatmentmarketed under the trademark SUBCHONDROPLASTY™. SUBCHONDROPLASTY™treatment may be useful for treating joint pain, such as knee pain,where sclerotic bone and an associated anomaly or defect such as bonemarrow lesion or edema is found. In some embodiments, bone marrowlesions or insufficiency fractures may be treated by SUBCHONDROPLASTY™using an open reduction, internal fixation of the bone's abnormal areaor area adjacent to the abnormality. In particular, inSUBCHONDROPLASTY™, the sclerotic bone may be treated using drilling andinsertion of an implant. In addition, an associated bone marrow lesionor edema may be treated by injection of a bone void filler, such as acalcium phosphate cement (CPC).

Based on the implant and surgical method, a subchondral region of thebone may be treated and strengthened to restore its strength/repairequilibrium. In addition, strengthening the bone reduces, reversesand/or prevents the deformation of overstressed bone, which may relievepain and slow arthritic disease progression within the underlying boneand adjacent meniscal tissues, such as cartilage.

In some embodiments, the invention provides an additional treatmentoption for patients suffering with arthritic pain, particularly in theknee. The method of the invention may be performed based on minor oroutpatient surgery. Thus, the risk of complications is expected to besignificantly less than with major arthritis surgery, such as moreinvasive procedures like high tibial osteotomy and partial or total kneereplacement. In some embodiments, the implant and methods stabilize thedefect in the subchondral (underlying) bone in order to prevent furtherbiomechanical breakdown of the subchondral region of the bone and of theadjacent meniscal tissues, and alleviate the corresponding pain in thejoint.

For example, the devices and methods of the present invention maypromote integration of the bone marrow lesion with the surrounding bone.In other words, the implant and methods may serve to bridge thesurrounding bone having one or more bone marrow lesions or boneinsufficiency fractures. The surrounding region may even be densesclerotic bone. In some embodiments, the implant may serve toredistribute the stress within the bone (especially in a weight bearingbone), and thus, may reduce pain. In other words, the implant mayessentially dampen or prevent the force transmission that causes painfrom the subchondral region of the bone. The implant is designed to haveoptimal stiffness and may be bioactive to facilitate the healingprocesses of the bone and integration of any abnormal areas, such asbone marrow lesions or insufficiency fractures, within the bone.

In a joint having a subchondral area of thinned or damaged bone, or anarea absent of cartilage, there often exists nearby defects such asinsufficiency fractures or fissures. Along with an insufficiencyfracture there is often a region of dense sclerotic bone, possiblycreated by the concentration of joint forces at this localized region.It is believed that, over time, the joint forces acting on this densesclerotic bone creates abnormal distribution of forces that lead toanomalies such as bone marrow lesions or edemas. The sclerotic boneregion can be identified using T1-weighted MRI, while the bone marrowlesion or edema can often be identified using T2-weighted MRI.

As noted, embodiments of the present invention may be explained andillustrated with reference to treatment of a patient's knee, though itis understood that the devices, instruments and methods of the presentinvention may be applicable to other joints as well, such as theshoulder, hip and ankle. Referring now to FIG. 1, an arthritic humanknee comprises a femur 10 and a tibia 12. Bone lesion 14 of tibia 12presents as a focally increased signal in the marrow in an MRI of theknee. In certain embodiments, coronal spin-echo fat-saturated protondensity, T1ρ proteoglycan and T2-weighted fat-saturated magneticresonance images are preferred. In some embodiments, bone lesions, whichare from 0 to 10 cm from the joint, 0 to 5 cm from the joint, or 0 to 1cm from the joint are considered good candidates for treatment.

A bone marrow lesion 14 or other abnormality causing pain can beidentified using magnetic resonance imaging (MRI), such as a T2-weightedMRI, but other identification means may be employed as well. Forexample, bone lesions can be identified using X-ray or Technetium-99bone scans. In embodiments employing MRI, any MRI technology thatreveals bone marrow lesions can be used, for example, open MRI, lowfield strength MRI, extremity MRI, whole body scanner MRI, and the like.In another embodiment, 3-dimensional imaging or image guidancetechnology may be employed to locate the lesion or defect. Such imagingtechnology would enable the lesion or defect to be locatedintraoperatively.

Various criteria may be employed for selecting an implant in accordancewith principles of the present invention. For example, a reinforcingmember 16 as an implant may be selected based on a grading system thatindicates an extent of treatment for various types and sizes of bonemarrow lesions or defects.

FIG. 1 shows just one example of how reinforcing member 16 could beimplanted in bone lesion 14. Of course, the reinforcing member 16 may beimplanted adjacent to the bone lesion 14. For example, the reinforcingmember 16 can be implanted adjacent to a side of the bone lesionproximal to the joint and/or adjacent to a side of the bone lesiondistal to the joint.

FIG. 1 shows one reinforcing member 16 implanted. Those skilled in theart will recognize that multiple reinforcing members can be implanted inand/or adjacent to a bone lesion according to other embodiments. Ingeneral, an implant that is 10 mm (or less) away from an outer surfaceof the bone lesion can be considered adjacent to that lesion. Adjacentreinforcing members can also be in contact with an outer surface of thebone lesion.

In general, the reinforcing member 16 serves to adequately distributestresses placed on the bone. The reinforcing member 16 may be bioactiveand configured to have an appropriate rigidity/flexibility and othercharacteristics, such as porous or non-porous coatings, as desired. Inparticular, the reinforcing member 16 may be sufficiently strong orstiff to make it capable of being implanted in bone and avoid stressconcentration, for example, in the subchondral region of the bone.Accordingly, the reinforcing member 16 may have various dimensions andstiffness.

In some embodiments, the implant is implanted free of bonds to the bone.Thus, the reinforcing member is not, for example, glued, cemented,stapled, stitched, clamped or screwed to the bone. However, the implantmay naturally or be configured to eventually bond to the bone viabiological processes in situ.

In some embodiments, the reinforcing member 16 is implanted in the bonein or adjacent the bone lesion such that a proximal face faces the jointand a distal face faces away from the joint. In addition, thereinforcing member 16 may be selected or modified (e.g., cut, torn,etc.) such that a maximum dimension of the proximal face exceeds amaximum dimension of the bone lesion. It is also within the scope of theinvention for the maximum dimension of the bone lesion to equal orexceed a maximum dimension of the proximal face. Thus, the reinforcingmember 16 can be larger, smaller or the same size as the bone lesion.

The reinforcing member 16 can be implanted such that the proximal faceis perpendicular to a longitudinal axis of the bone. In general,proximal and/or distal faces of the implant will be the primary loadbearing surfaces in situ.

In certain embodiments, a syringe (optionally with a needle) can be usedto inject a fluid into a bone so as to form the reinforcing member insitu. This step can be conducted with or without first creating anopening in the bone. The fluid is preferably a liquid, semi-solid, gel,hydrogel, dispersion or slurry. After injection, the fluid can remainfluid-like, or may cure to a more solid-like state. For example, theinjected fluid can cross-link or polymerize from a liquid to form asemi-solid, gel or solid. Fluids that cure in situ can be self-curing orcan cure in response to curing means, such as, e.g., radiation (e.g., UVlight), heat (e.g., body temperature), moisture and/or a curing agent.

In other embodiments, the reinforcing member is solid in nature and maybe rigid or malleable. In these embodiments, the surgeon creates a smallopening in the vicinity of the bone lesion. Suitable surgical tools forthis task include standard bone instruments (e.g., chisels, drills,etc.) and instruments, such as a guide/insertion instrument, designedfor use in the method of the invention.

A surgeon can implant the reinforcing member 16 by studying a previouslycaptured image of the bone marrow lesion 14 and manually estimating thelocation and boundaries of the bone lesion. Alternatively, a surgeon canbe provided with additional guidance during surgery. For example,surgery can be conducted using real-time imaging, robotic devices, oneor more braces that maintain the joint in a position consistent withcaptured images of the joint and/or labels, etc. Suitable labels includebut are not limited to radioactive labels, such as Technetium-99 andother objects, such as fiducial markers.

Postoperatively, patients may be required to maintain partial weightbearing and use ambulatory aids. Depending upon the physician'sdiscretion, full weight bearing may also be possible after surgery.Routine post intervention physical therapy may also be required.Patients may be treated according to routine post intervention care,observation and follow-up.

The reinforcing member 16 may have various forms and shapes to maximizeits surface area and reduce stress of the bone when implanted. Forexample, the reinforcing member 16 may be in the form of a rod having atriangular profile, a rectangular profile, or a circular profile.Reinforcing member 16 may be planar, e.g., relatively long in twodimensions and relatively short in a third dimension. Planar reinforcingmembers in accordance with the invention can have a thickness which is≦50% of the length and ≦50% of the width of a rectangular reinforcingmember (or ≦50% of the diameter in the case of a circular reinforcingmember or ≦50% of the height and ≦50% of the base in the case of atriangular reinforcing member).

In other embodiments, the reinforcing member 16 may have a wedge-shapededge on at least one edge or a wedge or ramp shape when viewed from theside. A wedge-shaped edge may be adapted to facilitate inserting thereinforcing member 16 into the bone. Thus, the particular angle andother dimensions of the wedge may be dictated by factors that are knownin the art. As a wedge-shaped implant, the reinforcing member 16 may besimilar to standard surgical tools, such as osteotomes, or compriseblade plates or osteotomy staples. Further, the reinforcing member 16may be an expandable device that can span the defect. In one embodiment,the reinforcing member 16 may be an expandable screw, such as anosseoscrew.

In other embodiments, the reinforcing member 16 may be in the form of aclosed disc, an open disc, a screw-shaped device, or an elongated pin.In addition, the reinforcing member 16 may have a square profile,rectangular profile with rounded edges, or an I-beam profile.Alternatively, the reinforcing member 16 can be an injection cementdiffuser. In some embodiments, the reinforcing member 16 may beapproximately 3 mm thick.

In some embodiments, the reinforcing member 16 may be customized to thepatient. For example, using 3-dimensional imaging technology, it may bedesirable to provide an implant that matches precisely the anatomicalsite where the reinforcing member 16 is to be placed. This would ensureconformability and avoid a less than perfect match between the implantand the implantation site.

The reinforcing member 16 may be porous and/or fenestrated to allow forbone ingrowth. Reinforcing member 16 comprises a physiologicallycompatible material that has sufficient durability to reinforce theoverstressed bone of the bone lesion and bear physiologic loads.Materials for the reinforcing member 16 can include metals, such astitanium, stainless steel, alloys of cobalt and chrome, tantalum, alloysof titanium and nickel and other superelastic metal alloys. Porous,titanium, titanium “foam”, tantalum, trabecular metals, nanoceramics,porous nitinol, or other highly porous nanomaterials, and chrome cobaltmay also be employed in the reinforcing member 16.

The reinforcing member 16 may comprise a functional coating, such as,hydroxyapatite plasma coating, titanium nitrate or bioactive glass. Inaddition, the reinforcing member 16 may undergo some form of surfacetreatment including acid etching, grit blast, or plasma spray. Thereinforcing member may also comprise structural enhancements such asmeshes, and include autograft. The member 16 may also be formed of, orinclude, porous metals like tantalum or ACTIPORE™.

Other embodiments comprise the use of bone, such as autografts,allografts, and artificial or synthetic bone substitutes. Certainembodiments comprise the use of polymeric materials. A combination ofmaterials, such as a porous metal applied to a carbon fiber implant maybe employed in the reinforcing member 16.

Reinforcing member 16 can be osteogenic, osteoconductive, and/orosteoinductive. Osteoconductive materials that may be used include butare not limited to collagen and the various forms of calcium phosphatesincluding hydroxyapatite, tricalcium phosphate, and fluoroapatite.Suitable osteoinductive substances include but are not limited to bonemorphogenetic proteins (e.g., rhBMP-2), demineralized bone matrix,transforming growth factors (e.g., TGF-beta), osteoblast cells, andvarious other organic species known to induce bone formation. Bonemarrow, blood plasma, or morselized bone of the patient, or commerciallyavailable materials may also be used.

The reinforcing member 16 may be treated prior to implantation. Forexample, the reinforcing member 16 may be dipped or coated with boneconductive or bone inductive material. Osteoinductive materials, such asBMP, may be applied to, for example, by immersing the reinforcing member16 in an aqueous solution of this material in a dilute suspension oftype I collagen. Osteoinductive materials such as TGF-beta may beapplied from a saline solution containing an effective concentration ofTGF-beta, or may be carried in the resilient material. Of course, otherbiologics may be applied by any method known in the art.

The reinforcing member can be resorbable or non-resorbable. For example,the reinforcing member 16 may comprise PEEK, PGA, or PLA material.Electrical stimulation can also be applied to the bone to promote bonehealing. The reinforcing member 16 may also be capable of imbibing bonestimulating material, such as porous nitinol, e.g., ACTIPORE™ or otherform of porous coated titanium or periapatite coated titanium.

In some embodiments, implantation of the reinforcing member 16 may beachieved step-wise in multiple stages. For example, the reinforcingmember 16 may be constructed to be implanted at an initial stage toestablish primary fixation, then at a subsequent stage additionalimplantation or assembly can be performed to add increased pull-outstrength and other reinforcing properties to the fully assembledreinforcing member 16.

FIGS. 2A and 2B show exemplary SUBCHONDROPLASTY™ kits 20. These kits 20are provided for facilitating the injection of bone void filler intosubchondral insufficiency fractures in a subchondral surgical procedurethat will be referred to under its marketed name as SUBCHONDROPLASTY™ orSCP™. As shown, the components of the kit may include, among otherthings, a SUBCHONDROPLASTY™ guide/insertion instrument 40, SCP™templates 50A, 50B, and various tools 60 for assessment and/or drilling.For example, the tools 60 provided in kit 20 may include a volumeassessment tool, a fixed bone portal 62, a Kirschner wire (or K-wire)64, a bore creation device, several injection catheters 66 sized tomatch the bore creation device, several syringes 68, and a portal holeplug. In some embodiments, the kits 20 are provided to surgeon ormedical facility pre-packaged and sterile. In addition, some or all ofthe instruments and tools provided in the kit 20 may be reusable ordisposable.

The kits 20 may also include a cavity creation device (not shown inFIGS. 2A and 2B). Cavity creation devices may include burrs, punches,reamers, rongeurs, tamps, drills 70, instruments with expandablecomponents, such as balloons, stents or looped wires, instruments with aselectively angulatable or reconfigurable distal ends, and others knownin the art.

As shown, in FIG. 2A, a first embodiment of the kit 20 can include anassortment of reinforcing members, such as reinforcing member 16, ofvarious sizes and/or shapes appropriate for use with a variety of bonelesions. The kit 20 can also include instructions for use, e.g., printedon the container and/or on inserts within the container. The kit 20 canstill further include a tool for adjusting the size of the reinforcingmember 16, a hammer for driving the reinforcing member 16 into the boneand/or a bone filler to seal the open end of the channel in the bone inwhich the reinforcing member 16 resides. As noted, the kit 20 may beprepackaged and sterile with an assortment of reusable or disposableinstruments and tools.

Suitable bone fillers include but are not limited to materialscomprising beta-tricalcium phosphate (e.g., VITOSS, PROOSTEON 500R madeby E-Interpore-Cross International), hydroxyapatite (e.g., OSTEOGRAFmade by Ceramed Denta, Inc., Lakewood, Colo.), calcium carbonate,calcium sulfate (e.g., OSTEOSET and ALLOMATRIX made by Wright MedicalTechnology, Inc.), calcium phosphate (e.g., CALCIBON made by Merck &Co., Inc., Whitehouse Station, N.J. and NORIAN SRS made bySynthes-Strates, Switzerland), synthetic bone fillers (e.g., CORTOSS)and/or processed bone fillers (e.g., BIOOSS made by GeistlichBiomaterials, Inc., Switzerland). Other suitable materials may includehydrogels, PEEK (polyetheretherketone), carbon fiber, polycarbonateurethane (PCU), stem cells with and without matrices, collagen with andwithout matrices and carriers, pharmacotherapeutic with and withoutmatrices and carriers, hyaluronic acid with and without matrices, insitu curable materials with and without anti-inflammatory agents,demineralized bone matrix, allograft, biocompatible metals, resorbablePCA, PGLA, and polyurethane, hydroxyapatite, calcium sulfate, BMP growthfactor, TGF-β super family, MP52, TP508, bioactive glass, sodiumalignate, AOC based carrier and active components (synthetic beeswax),and starch.

In some embodiments, the bone filler may be of a type that can expandupon insertion into the void. For example, the filler may be injectableat the defect site, whereupon it can fill up or expand into the void.And as with the reinforcing member 16, the bone void filler may also beimplanted in a step-wise fashion such that an initial stage to establishprimary fixation is followed with a subsequent stage of assembly thatprovides added strength and bone integration properties to the fullyassembled bone void filler.

As shown in FIG. 2B, another embodiment of the kit 20 can include afluid, a syringe for injecting the fluid into a bone and a containeradapted to maintain the sterility of the contents of the container. Asnoted, the kit 20 may be prepackaged and sterile with an assortment ofreusable or disposable instruments. This embodiment of the kit 20 canfurther comprise a needle and premeasured portions of ingredients in aplurality of separate vials. As with the first embodiment of the kit 20,this embodiment can optionally include instructions for use, e.g.,printed on the container and/or on inserts within the container. The kit20 can further include bone tools for providing a channel in the bone inwhich the fluid is injected and/or a bone filler to seal the open end ofthe channel in the bone in which the reinforcing member resides.

The kit 20 can further include curing agents (i.e., polymerizing agents,catalysts and/or cross linking agents) as separate ingredients to beadded to the injected fluid. The kit 20 can include other curing means,such as a UV light source or other device for generating radiation. Thefluid can be preloaded in the syringe for injection. In someembodiments, a multiple barrel syringe can be included for in situmixing of ingredients that must be stored separately in differentbarrels of the syringe (e.g., monomers and polymerizing agent, orpolymers and cross linking agent, etc.).

FIG. 3A shows a SUBCHONDROPLASTY™ template 50A of the kit 20 from FIG.2A in use. FIG. 3B shows a SUBCHONDROPLASTY™ template 50B of the kit 20from FIG. 2B in use. As part of the pre-operative planning process,medical imaging, such as an MRI illustrated in FIG. 1, is taken of theknee of a patient suffering from arthritic pain. For purposes ofclarity, FIGS. 3A and 3B show the templates 50A, 50B overlaying asimplified illustration of a knee. A subchondral insufficiency fracture92 associated with lesion 14 may then be identified and located on theMRI. The fracture size, volume and orientation are determined from theimage, and based on the values, the recommended volume of bone voidfiller is determined from the volume assessment tool.

The SCP™ templates 50A and 50B, shown in FIGS. 3A and 3B, may be atransparent to indicate how a lesion can be treated. In use, forexample, the templates 50A and 50B are placed over the MRI image todetermine the placement of the SCP™ guide/insertion instrument 40, theappropriate location for a bone portal 62, and the resulting depth tothe fracture.

FIG. 4A shows an exemplary embodiment of a SUBCHONDROPLASTY™guide/insertion instrument 40. As shown, the guide/insertion instrument40 may comprise an integrated cartilage reference 42, a paralleldrill/implant guide 44, and angular drill guide/portal 46

The SCP™ guide/insertion instrument 40 is included in the kit 20 to aimthe bone portal 62 and to set the depth stop of drilling for thesurgeon. As shown, the SCP™ guide/insertion instrument 40 may comprise acurved body, a probe, and an optional adjustable arm (not shown). Thecurved body has a radius of curvature that provides for different anglesof approach to the tip of the probe. The probe is attached to the curvedbody and may have a planar, rasped tip for contacting and gripping thearticular surface of the knee joint without damaging the cartilage. Theoptional adjustable arm (not shown) may be connected to the curved bodythrough a sliding arrangement such that the angle of the arm isadjustable with respect to the curved body.

FIG. 4B shows another exemplary embodiment of the SUBCHONDROPLASTY™guide/insertion instrument 40. As shown, in this embodiment, the SCP™guide/insertion instrument 40 may comprise a detachable handle 48. Thedetachable handle 48 may be detachable in order to facilitate itsmanipulation during surgery. The detachable handle 48 may be detachablebased on various mechanisms that are known to those skilled in the art.

FIG. 5 illustrates a side view of the SCP™ guide/insertion instrument 40and various options of the instrument 40. As shown, the probe of theSCP™ guide/insertion instrument 40 may comprise integrated cartilagereference 42 and parallel drill/implant guide 44. The guide 44 isconfigured to guide a drill 70 or other tool to a location or target Tindicated by the cartilage reference 42. In addition, in the embodimentshown, the curved body of the SCP™ guide/insertion instrument comprisesan angular drill guide/portal 46. The guide/portal 46 may provide a setof guides/portals that converge at location T from various angles, suchas 30 degrees and 45 degrees.

FIG. 6 illustrates a perspective view of the various options of theSUBCHONDROPLASTY™ guide/insertion instrument 40. As shown, the paralleldrill/implant guide 44 may comprise a series of holes/portals in amatrix configuration to help guide a drill 70 or other tool to locationT.

FIG. 7A shows another embodiment of a SUBCHONDROPLASTY™ guide/insertioninstrument 40 and side view of how it may be placed relative to a kneeduring surgery. FIG. 7B shows the SUBCHONDROPLASTY™ guide/insertioninstrument 40 and a perspective view of how it may be placed relative toa knee.

FIGS. 8, 9A-9J, 10A-10B, 11A-11C illustrate a method of treating a kneebased on embodiments of the present invention. As noted, medicalimaging, such as an MRI, is taken of the knee of a patient sufferingfrom arthritic pain. A bone marrow lesion, such as a subchondralinsufficiency fracture 92, is identified and located on the MRI. Thefracture size, volume and orientation are determined from the image, andbased on the findings, the recommended volume of bone void filler isdetermined from the volume assessment tool. The SCP™ template, shown inFIGS. 3A and 3B, is a transparency with a plurality of curved linesbetween two intersecting straight lines. In use, the template 50 isplaced over the MRI image to determine the placement of the SCP™guide/insertion instrument 40, the appropriate location for the fixedbone portal 62, and the resulting depth to the fracture.

Referring now to FIG. 8, the SCP™ guide/insertion instrument 40 may bepositioned such that the location T of the cartilage guide 42 is in onor adjacent to the bone marrow lesion of interest. In use, the SCP™guide/insertion instrument 40 is placed proximate to the joint. Theprobe may be visually placed on the articular cartilage, for example,using arthroscopy. If present, any cartilage defect can be used toassist probe placement.

The SCP™ guide/insertion instrument 40 helps determine the access pointand angle for the K-wire (included in the kit 20), which may be used bythe surgeon. For example, in some embodiments for treating a patient'sknee, the SCP™ guide/insertion instrument 40 is configured to treatsubchondral bone that is within 5 mm below the tibial surface. In someembodiments, the SCP™ guide/insertion instrument 40 has a planar, raspedtip for contacting and gripping the articular surface of the knee jointwithout damaging the cartilage.

Using parallel drill/implant guide 44, a surgeon may then drillparallel, for example, to the articular surface of a patient's knee. Insome embodiments, the surgeon drills through or adjacent to the bonemarrow lesion.

Referring now to FIG. 9A, the surgeon may then drill at an angle tolocation T of the bone marrow lesion 92 via angular drill guide/portal46. The surgeon may select the angle of approach based on a variety offactors, such as the location of the bone marrow lesion, size of thelesion, access to the knee, etc. While the SCP™ guide/insertioninstrument 40 is held in place, a K-wire is inserted through the lumenin the adjustable arm and into interior of the bone. Fluoroscopy may beused to verify the position and depth of the wire with respect to thefracture 92. The SCP™ guide/insertion instrument 40 may then be removed,but the K-wire retains the angle and depth to the fracture 92.

FIGS. 9B-9D illustrate in further detail how a surgeon may drill at anangle to a bone marrow lesion 92. As shown, the surgeon may install abone portal 94, for example, using the SCP™ guide/insertion instrument40 (not shown).

In use, the SCP™ guide/insertion instrument 40 is placed proximate tothe joint. Based on the information determined from the SCP™ template,the probe tip of SCP™ guide/insertion instrument 40 is placed on atarget location on the articular surface of the knee joint, i.e., in oradjacent to the bone marrow lesion. As noted above, in order to treatknee pain, the bone marrow lesion 14 may be a meniscal defect associatedwith an underlying subchondral insufficiency fracture 92.

The guide/insertion instrument 40 is used to aim a bone portal angle andto set the bone portal depth stop based on the information determinedfrom the SCP™ template. The SCP™ guide/insertion instrument 40 may thenbe removed and the bone portal retains the angle to the fracturelocation. During surgery, the bone portal may also hold or steady theSCP™ guide/insertion instrument 40.

The bone portal 62 (included in the kit 20) provides an entry point inthe bone for an instrument to gain access to the interior of the boneand to the subchondral insufficiency fracture 92. The bone portal 62 maybe a single component design having an elongate body. The distal end ofthe body may include external threads for anchoring the portal 62 to thecortex of the bone. In some embodiments, the portal 62 has an outerdiameter of approximately 8 mm. The size of a particular bone portal 62is selected to support the cortex and prevent possible damage andweakening of the surrounding cortex. The body of the bone portal 62 hasa lumen for receiving an instrument therein and a length that allows foran accurate trajectory to the bone marrow lesion 14. The proximal end ofthe body has a depth stop for limiting the extent an instrument receivedwithin the lumen may be inserted into the interior of the bone. Tofacilitate the ease of implementing the SUBCHONDROPLASTY™ treatment, thebone portal 62 may serve as a working channel, enabling a multitude ofinstruments to pass through the same access point.

In use, the bone portal 62 can be threadedly anchored to the bone cortexat a location determined from the MRI template. As shown, the boneportal 62 is installed at an angle perpendicular to the bone cortex,resulting in better coupling. Alternatively, the surgeon may use anadjustable bone portal 62 that allows for repeated entry into the bonefor multiple fractures to be treated with a single bone portalinsertion. The portal 62 may be made of a resorbable material, in whichcase it could provide as an implant left in the cortex after the SCP™procedure is completed. Furthermore, the bone portal 62 may beradiolucent and have at least one marker for identification underimaging.

The surgeon may then drill through the SCP™ guide/insertion instrument40 via angular drill guide/portal 46 (not shown) to create a bone cavity96 to bone marrow lesion (as shown in FIG. 9D). The drill may be acannulated drill 70, for example that is used over the K-wire to enlargethe channel to the fracture 92. Other bore creation devices known in theart may be used, including biopsy needles, punches, burrs, reamers,rongeurs and tamps, as well as other types of drills.

FIG. 9E illustrates how the surgeon may then employ a Kirschner wire orK-wire at the site of bone marrow lesion 92. Alternatively, FIG. 9Fshows the use of an adjustable bone portal 98 that allows the surgeon toselect one or more angles provided by angular drill guide/portal 46 or,for example, to treat multiple sites.

The adjustable bone portal shown in FIG. 9F may be included in the kit20 to provide an entry point in the bone for different instruments togain access to the interior of the bone and to a subchondralinsufficiency fracture 92, as previously mentioned. In general, theadjustable bone portal has a body component and base component. The basecomponent includes external threads for anchoring the portal to thecortex of the bone and a central opening for receiving the bodycomponent. The outer diameter of the base component is approximately 8mm, selected to support the cortex and prevent possible damage andweakening of the surrounding cortex with a portal with a largerdiameter. The body component may have a lumen for receiving differentinstruments, and a length that allows for an accurate trajectory to thedefect. A proximal end of the body component has a depth stop forlimiting the extent an instrument received within the lumen may beinserted into the interior of the bone. The depth stop may be adjustedaccording to the depth of the defect within the bone, as measured fromthe entry point.

In some embodiments, adjustability of the bone portal is achievedthrough a ball-and-socket arrangement between a socketed central openingin the base component and a ball shaped distal end of the bodycomponent. A lock mechanism can be provided to maintain the base andbody components in a desired position relative to each other. In anotherembodiment, adjustability of the bone portal is achieved through aconically shaped central opening in the base component. A lockingmechanism can be provided to maintain the base and body components in adesired position relative to each other.

FIGS. 9G-9J illustrates the various ways that a surgeon may treat a kneevia bone cavity 96. A cavity creation device is used after a borecreating device is removed to leave an enlarged channel to the fracture,and prior to the bone void filler being prepared As shown, the surgeonmay use a K-wire with a depth stop (included in the kit 20) to create anaccess channel to the subchondral insufficiency fracture 92. As shown inFIG. 9G-9J, the K-wire is inserted through the lumen of the bone portalbody to the desired depth, which will be reached when the K-wire depthstop contacts the bone portal body depth stop. The K-wire is preventedfrom being advanced through the articular surface. Fluoroscopy may beused to verify the K-wire position and depth with respect to thefracture. If placement is incorrect, the K-wire can be retracted and thebone portal readjusted. The K-wire 64 is then removed.

The surgeon may use a bore creation device (also included in the kit 20)to enlarge the access channel created by the K-wire 64 to the fracture.The bore creation device can be an 8-gauge biopsy needle, a core punch,or a fenestrated drill. Each can be provided with a depth stop toprevent penetration through the articular surface of the bone. Otherbore creation devices known in the art may be used, including burrs,reamers, rongeurs and tamps, as well as other types of biopsy needles,punches and drills. A cavity creation device in the form of a burr, forexample, is inserted through the lumen in the bone portal to the desireddepth and is manually moved or activated to create a cavity. Dependingon the device used, this may be accomplished by cutting bone,compressing bone, or a combination.

As shown, the surgeon may use a cannulated drill, for example, beinginserted through the lumen of the bone portal body until the drill depthstop contacts the bone portal body depth stop. The drill is preventedfrom being advanced through the articular surface. The drill is thenremoved, leaving an enlarged channel 96 to the fracture 92.

In another embodiment, a series of cannulas or bone dilators ofprogressively increasing diameter may be provided. The cannulas ordilators may be used to progressively bore concentric openings withinthe subchondral bone.

FIG. 10A illustrates another step that a surgeon may perform to treat apatient's knee. In particular, the surgeon may inject bone void filler,such as calcium phosphate (CaP) or a bone cement, such as a lowviscosity Poly-methyl methacrylate (“PMMA”). During surgery, aninjection catheter 66 is filled with a volume of the bone void filler,which was determined from the volume assessment tool (included in thekit 20). FIG. 10A shows the injection catheter 66 being inserted andsealed to the bone portal. Cement in the catheter 66 prevents boneshards and debris from clogging the catheter 66. Under fluoroscopy, thebone cement is injected from the catheter 66 into the subchondralinsufficiency fracture 92 using a syringe 68 with volume and ratecontrols. The syringe 68 provides tactile feedback as the bone cement isdispensed to fill the fracture and then interdigitate with theimmediately surrounding cancellous bone. The catheter 66, syringe 68 andbone portal 62 may then be removed.

In order to prevent bone void filler from leaking out of the hole thatremains in the cortex after removal of the bone portal, a portal holeplug (provided in the kit 20) may be used. Alternatively, the bone thatwas removed using the bore creation device during the channelenlargement step may be sized and shaped as a plug to fill the portalhole. Of note, the injection of a bone void filler can be before orafter the implantation of reinforcing member 16. If desired, the bonemarrow lesion or edema may be aspirated prior to insertion of theimplant or infusion of the bone void filler. This aspiration step may beperformed through the angular drill guide/portal 46, and suction may beperformed through the parallel drill/implant guide 44.

For example, as shown, an 8-gauge needle 102 may be guided via paralleldrill/implant guide 44 in or adjacent to the bone marrow lesion. FIG.10B illustrates another view of the surgeon injecting CaP cement via theparallel drill/implant guide 44. In some embodiments, the surgeon maydrill one or more holes at various locations. In addition, the surgeonmay leave the drill bits in place in order to stability the SCP™ toolguide 40.

Alternatively, the surgeon may insert one or more bone conductive pinsthrough the SCP™ tool guide 40 and into pre-drilled holes. After theimplants have been implanted, the SCP™ tool guide 40 may be removed andpins cut flush to the bone surface.

FIGS. 11A-11C illustrate another step that a surgeon may perform totreat a patient's knee. For example, FIG. 11A shows a side view ofsurgeon injecting CaP cement in or adjacent to a bone marrow lesionusing 8-gauge needles 102. As shown, the 8-gauge needles 102 are guidedusing SCP™ guide/insertion instrument 40 to converge in or adjacent tobone marrow lesion. Alternatively, as shown in FIG. 11B, once the drillshave been inserted, the surgeon may remove the SCP™ guide/insertioninstrument 40 (not shown) and guide an 8-gauge needle 102 over the drillto inject CaP cement in or adjacent to the bone marrow lesion. Forexample, a catheter 66 filled with bone cement is then injected into thebone cavity 96 to fill the cavity and then any interstitial space ofsurrounding uncompressed cancellous bone.

FIGS. 12-16 illustrate a method of treating a bone based on anotherembodiment of the present invention. In particular, as shown in FIG. 12,the SCP™ guide/insertion instrument 40 may comprise a detachable handlethat the surgeon removes initially to position the guide/insertioninstrument 40, for example, on the articular surface. Referring now toFIG. 13, the surgeon may then drill via parallel drill/implant guide 44towards the site of a bone marrow lesion (not shown).

As shown in FIG. 14, the surgeon injects CaP cement using an 8-gaugeneedle over the drill in or adjacent to the bone marrow lesion. Next, asshown in FIG. 15, the surgeon may reattach the detachable handle 48 tothe SCP™ guide/insertion instrument 40 and drill in or through the bonemarrow lesion (not shown) via angular drill guide/portal 46. As shown inFIG. 16, if desired, the surgeon may then inject CaP cement using acannula with injection port or fenestrated distal tip for targetplacement or dispersion of the bone void filler, or the 8-gauge needle102, over the drill to inject CaP cement in or adjacent to the bonemarrow lesion via angular drill guide/portal 46.

While the invention is described in the context of osteoarthritis of theknee, it is not limited to such condition. Other conditions that can betreated in accordance with the invention include but are not limited toosteoarthritis of joints other than the knee, such as the shoulder, hipand ankle. For example, the SUBCHONDROPLASTY™ treatment may be used totreat other joints, such as the shoulder, hip, and ankle. Moreover, insome embodiments, the SUBCHONDROPLASTY™ treatment may be coupled toother forms of joint pain treatment. For instance, in the knee, theSUBCHONDROPLASTY™ treatment may be employed in conjunction with amicrofracture, arthroscopic/arthrosurface, uni-knee replacement, orpartial bone resurfacing procedure. In such cases, the SUBCHONDROPLASTY™procedure itself becomes a component in a multi-step treatment processto address the overall pain management and treatment of the joint.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of thedisclosure provided herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the disclosure being indicated by the following claims.

1. A method for treating joint pain comprising: identifying a source ofthe pain of the joint based on an image of the joint, the imageindicating the presence of a defect in the subchondral region of a boneof the joint; locating an insufficiency fracture in the subchondralregion of the joint; mapping an access path to a location in thesubchondral region where the insufficiency fracture resides, wherein theaccess path preserves an articular surface of the joint; and implantingin the bone, via the access path, a reinforcing member that stabilizesthe insufficiency fracture.
 2. The method of claim 1, wherein implantingthe reinforcing member comprises injecting a flowable material.
 3. Themethod of claim 1, wherein the flowable material comprises a bone voidfiller, bone substitute material, or a bone cement.
 4. The method ofclaim 1, wherein the flowable material stimulates bone growth.
 5. Themethod of claim 4, wherein the flowable material includes calciumphosphate.
 6. The method of claim 2, wherein the flowable materialintegrates the insufficiency fracture with surrounding bone tissue. 7.The method of claim 1, wherein a subchondral defect is further presentnear the insufficiency fracture.
 8. The method of claim 7, wherein thesubchondral defect comprises a bone marrow lesion.
 9. The method ofclaim 7, wherein the subchondral defect further includes sclerotic bone.10. The method of claim 7, wherein the insufficiency fracture is aresult of the subchondral defect.
 11. The method of claim 8, furtherincluding evaluating the bone marrow lesion based on a location of thebone marrow lesion and a size of the bone marrow lesion from the imageof the joint.
 12. The method of claim 11, wherein evaluating the bonemarrow lesion comprises assessing the bone marrow lesion based on itsproximity to a periphery of the bone.
 13. The method of claim 8, whereinmapping the access path further includes creating access to the locationof the bone marrow lesion.
 14. The method of claim 13, wherein creatingaccess comprises measuring a location of the bone marrow lesion based ona coordinate system that originates from an anatomic landmark on thebone.
 15. The method of claim 1, wherein mapping the access furtherincludes creating access by drilling.
 16. The method of claim 14,wherein the coordinate system corresponds to predetermined settings ofan instrument guide.
 17. The method of claim 9, further includingremoving bone tissue and at least a portion of the sclerotic bone fromthe bone prior to implanting the reinforcing member.
 18. The method ofclaim 1, wherein the reinforcing member is an implantable device. 19.The method of claim 18, wherein the implantable device is a bone plug.20. The method of claim 1, wherein the access path comprises an inferiorapproach into the bone towards the insufficiency fracture.
 21. Themethod of claim 20, wherein the inferior approach comprises an approachat an angle of about 30 to about 45 degrees.
 22. The method of claim 1,further comprising resurfacing the articular surface of the joint. 23.The method of claim 22, further including removing the reinforcingmember prior to resurfacing.
 24. The method of claim 20, furtherincluding assessing an effectiveness of the reinforcing member prior toresurfacing.
 25. The method of claim 1, wherein identifying the sourceof the pain of the joint based on an image of the joint comprisesevaluating a magnetic resonance image of the joint.
 26. The method ofclaim 9, wherein identifying the source of the pain of the jointcomprises identifying the bone marrow lesion based on a T2-weightedmagnetic resonance image joint and identifying the sclerotic bone basedon a T1-weighted magnetic resonance image of the joint.
 27. Aninstrument for guiding a tool to a target location in a bone adjacent toa joint, comprising: a first portion having a first guide sectionconfigured to guide the tool to the target location; a reference probeextending from the first portion having a tip that indicates a selectedlandmark on the bone; and a handle portion coupled to the first portionand having a second guide section configured to guide a tool to thetarget location; wherein the first guide section is configured to guidethe tool at an angle substantially parallel to the reference probe, andthe second guide section is configured to guide the tool at an angleacute to the reference probe.
 28. The instrument of claim 27, whereinthe guide sections comprise one or more openings for insertion of thetool therethrough.
 29. The instrument of claim 27, wherein the tool is adrill, pin, implantable device delivery tool, guidewire, bone portal,rongeur, or hammer.
 30. The instrument of claim 27, wherein thereference probe is configured to rest against an anatomical landmark onthe bone adjacent to the joint.
 31. The instrument of claim 27, whereinthe openings are configured to guide the tool into a subchondral regionof the bone.
 32. The instrument of claim 27, wherein the instrument is aunitary body.
 33. The instrument of claim 27, wherein the handle portionis configured to be detachable from the instrument.
 34. The instrumentof claim 27, wherein the handle portion is configured with a radius ofcurvature that provides a plurality of acute angles of approach to thetarget location.
 35. The instrument of claim 27, wherein the handleportion comprises an adjustable arm that provides an adjustable set ofangles of approach to the target location.